In order to prove Theorem REF , we will need to present in some details
the bases of the theory of SRCF. This theory is exposed in Perron's book
[1]} and, to our knowledge, it has not been updated since then. Besides,
some proofs can be simplified, as we are interested here only in infinite
SRCF. Thus, we will study first some basic properties of infinite SRCF in
Section . In Sections  and  respectively
we will prove formulas for the irrationality exponents of NCF and LCF by
transforming them into RCF. In particular, we will give in Theorem
REF  examples of NCF for which (REF ) is not valid. In Section
, we will state and prove Theorem REF , which gives
a rather general formula allowing to compute irrationality exponents. In
Section  we will prove Theorem REF  and Corollary
REF . Finally, we will give some examples of application of Corollary
REF  in Section .
